TRIBOCHEMICAL STUDY OF HYDROGENATED CARBON COATINGS WITH DIFFERENT HYDROGEN CONTENT LEVELS IN ULTRA-HIGH-VACUUM

Hydrogenated carbon films (CHx) with different hydrogen content percen tages have been examined. Drag tests on. CHx coated disks, using 50 pe rcent Al2O3/TiC sliders, with and without carbon coating art the slide r air bearing surfaces (ABS), were conducted in an ultra high vacuum c hamber equipped with a mass spectrometer. Mass fragments of lubricant released from the head disk interfaces were recorded in real time alon g with friction measurements. The results show that a higher hydrogen content in the carbon overcoat can improve wear durability by reducing the friction coefficient and affecting the chemical reactions between the sliders and the lubricant. A carbon overcoat on the slider ABS ca rt protect Z-dol lubricant from catalytic reaction with the Al2O3 in t he slider material. The wear durability at the head disk interface is controlled by combined mechanical and chemical factors, which are defi ned by the atomic structures of the contacting surfaces.